The big 7mm’s

Turtle566

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Townsville, Queensland, Australia
Hi all, I am after some information regarding the 7mm Mashburn Super Magnum, and how does it stack up against the 7STW and the 7 Remington Magnum, 7Rum.
I know there is a lot of conjecture about the 7Rum V’s 7STW, l look forward to your responses
Regards 🐢
 

jimbires

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clearfield county , Pa
I have a 7 Mashburn super mag , I like it . it's an 8.25 pound , 25" bbl . It does take components for fire forming , and I deal with donuts from necking down 300 win mag brass . is it worth all the messing around ,sometimes I wonder , you'll have to figure that out for yourself . It handles 175 gr bullets easily at 3000 + FPS . all the specs are wrote on these targets . the red target is 100 yards ,the green target is 200 yards . for awhile STW brass was hard to find , 300 win mag brass will always be available .
 

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Turtle566

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Location
Townsville, Queensland, Australia
Hi Jimbires, thank you for the information, also where did you get your die’s from? I like the fact that they are not common and over here, no one has even heard of them, 300 win mag brass is very readily available (we are lucky to not have the shortages that are plaguing the USA).
I have a Defiance Deviant Tactical Action and a Maddco 7mm barrel, getting the reamer from the USA and having a custom timber stock made for it.
Your info is really good, once again, thank you 😊🙏
 

JMGamesniper19

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Feb 16, 2016
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If you are looking for a big 7 magnum, have you taken a look at the 7mm-300 Norma Imp mag? This cartridge is capable of running the 195 EOL at well over 3200. 300 Norma brass is pretty available during normal times and the cartridge is comparatively easier on barrel life than some of the others due to case design.
I did a ton of research before building mine. To me, it is the best of all worlds in an overbore magnum
 

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JMGamesniper19

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I went 7mm Norma Mag Improved.

That's it on the left, with a 7 LRM on the right.
PAlsYDTh.jpg
So did I actually - the one on the left is a wildcat I did in 7MM PRC with a 175 eldx, on the R is the IMP with a 195 EOL
 

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jimbires

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Mar 16, 2008
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1,981
Location
clearfield county , Pa
Hi Jimbires, thank you for the information, also where did you get your die’s from? I like the fact that they are not common and over here, no one has even heard of them, 300 win mag brass is very readily available (we are lucky to not have the shortages that are plaguing the USA).
I have a Defiance Deviant Tactical Action and a Maddco 7mm barrel, getting the reamer from the USA and having a custom timber stock made for it.
Your info is really good, once again, thank you 😊🙏



got my form dies from CH4D ( I'm not sure why the link says enviro test ?)


I'm using RCBS set # 56234 full length and seater
 

jimbires

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Location
clearfield county , Pa
you can buy brass with the correct head stamp from these two places . I bought some of the quality brass , I haven't shot any yet . I'll need the correct head stamp to cross the border into Canada for a moose hunt , covid permitting .




when I form brass from 300 win mag , my fire form load is ;
65.0 grain IMR4350 , Hornady 139 gr spbt , fed 215 primer , .015 jump . this load shoots well , and nicely forms the brass . sorry I don't have a target with the specs on it , so I can't give you the velocity . I'd say about any bullet in the 140 grain weight would work for this . I use the Hornady 139's , since I have a bunch of them .
 

dogz

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Jan 11, 2006
Messages
833
Location
SWMT
Hi all, I am after some information regarding the 7mm Mashburn Super Magnum, and how does it stack up against the 7STW and the 7 Remington Magnum, 7Rum.
I know there is a lot of conjecture about the 7Rum V’s 7STW, l look forward to your responses
Regards 🐢


RUM has the bigger engine, hensce more speed as long as the pressures are apples to apples...........:)
 

Turtle566

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Joined
Oct 8, 2018
Messages
63
Location
Townsville, Queensland, Australia
got my form dies from CH4D ( I'm not sure why the link says enviro test ?)


I'm using RCBS set # 56234 full length and seater

you can buy brass with the correct head stamp from these two places . I bought some of the quality brass , I haven't shot any yet . I'll need the correct head stamp to cross the border into Canada for a moose hunt , covid permitting .




when I form brass from 300 win mag , my fire form load is ;
65.0 grain IMR4350 , Hornady 139 gr spbt , fed 215 primer , .015 jump . this load shoots well , and nicely forms the brass . sorry I don't have a target with the specs on it , so I can't give you the velocity . I'd say about any bullet in the 140 grain weight would work for this . I use the Hornady 139's , since I have a bunch of them .

Hi Jimbires, the information you sent me is the very stuff I have been looking for, living in Australia, it is a bit more difficult to find the right businesses in the USA, l don’t think you have any idea how much you have helped me, if I can help you with anything, (well almost) just yell out, if you ever want to come over to Australia, let me know and I can organise a few Stations for you to shoot on(Roos,Pigs & camels).Thats if the Covid ever stops.
My build is a slow one, but allows me to get the best of stuff and to modify as I go, the 7-300 Norma improved looks very interesting, but I think I will stick with the Mashburn as it’s not a barrel burner according to the info I can find.
Regards 🐢
 

jimbires

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Joined
Mar 16, 2008
Messages
1,981
Location
clearfield county , Pa
Hi Jimbires, the information you sent me is the very stuff I have been looking for, living in Australia, it is a bit more difficult to find the right businesses in the USA, l don’t think you have any idea how much you have helped me, if I can help you with anything, (well almost) just yell out, if you ever want to come over to Australia, let me know and I can organise a few Stations for you to shoot on(Roos,Pigs & camels).Thats if the Covid ever stops.
My build is a slow one, but allows me to get the best of stuff and to modify as I go, the 7-300 Norma improved looks very interesting, but I think I will stick with the Mashburn as it’s not a barrel burner according to the info I can find.
Regards 🐢


Turtle566,
if I can offer you any more help , just ask . your offer is way more than generous , thank you . good luck on your build , Jim
 

dan belisle

Member
Joined
Mar 6, 2002
Messages
17
Location
Alberta
you can buy brass with the correct head stamp from these two places . I bought some of the quality brass , I haven't shot any yet . I'll need the correct head stamp to cross the border into Canada for a moose hunt , covid permitting .




when I form brass from 300 win mag , my fire form load is ;
65.0 grain IMR4350 , Hornady 139 gr spbt , fed 215 primer , .015 jump . this load shoots well , and nicely forms the brass . sorry I don't have a target with the specs on it , so I can't give you the velocity . I'd say about any bullet in the 140 grain weight would work for this . I use the Hornady 139's , since I have a bunch of them .
Ive never heard of a requirement for properly labelled brass in Canada. Some African countries, yes. - dan
 

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